c2dc3dc78e
This provides a basic LVM support to dib-block-device. Co-Authored-By: Ian Wienand <iwienand@redhat.com> Change-Id: Ibd624d9f95ee68b20a15891f639ddd5b3188cdf9
428 lines
14 KiB
Python
428 lines
14 KiB
Python
# Copyright 2017 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import collections
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import logging
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import os
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import tempfile
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from diskimage_builder.block_device.exception \
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import BlockDeviceSetupException
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from diskimage_builder.block_device.plugin import NodeBase
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from diskimage_builder.block_device.plugin import PluginBase
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from diskimage_builder.block_device.utils import exec_sudo
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logger = logging.getLogger(__name__)
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#
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# LVM
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# ---
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#
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# The LVM config has three required keys; pvs, vgs and lvs
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#
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# lvm: -> LVSNode
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# pvs: -> PvsNode
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# lvs: -> LvsNode
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# vgs: -> VgsNode
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#
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# The LVMPlugin will verify this and build nodes into the
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# configuration graph.
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#
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# As described below, a LVSNode is created for synchronisation
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# purposes. Thus if you had something like two partitions that became
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# two physical-volumes (pv1 & pv2), that you then combine into a
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# single volume group (vg) and then create several logical volumes
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# (lv1, lv2, lv3) your graph would end up looking like:
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#
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# partition1 partition2
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# | |
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# ---> LVSNode <--+
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# |
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# +------+------+
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# v v
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# pv1 pv2
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# | |
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# +--> vg <---+
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# |
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# +-----+-----+
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# v v v
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# lv1 lv2 lv3
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#
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# After the create() call on the LVSNode object, the entire LVM setup
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# would actually be complete. The other nodes are all just
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# place-holders, and are used for further ordering (for example, the
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# fs creation & mounting should depend on the logical volume nodes).
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# For this reason, their create() calls are blank. However, for code
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# organisational purposes they have a private _create() and _cleanup()
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# call that is driven by the LVSNode object.
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class PvsNode(NodeBase):
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def __init__(self, name, state, base, options):
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"""Physical volume
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This is a placeholder node for the LVM physical volumes.
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Arguments:
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:param name: Name of this node
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:param state: global state pointer
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:param base: Parent partition
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:param options: config options
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"""
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super(PvsNode, self).__init__(name, state)
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self.base = base
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self.options = options
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def _create(self):
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# the underlying device path of our parent was previously
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# recorded into the state during blockdev creation; look it
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# up.
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phys_dev = self.state['blockdev'][self.base]['device']
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cmd = ["pvcreate"]
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cmd.append(phys_dev)
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if self.options:
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cmd.extend(self.options)
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logger.debug("Creating pv command [%s]", cmd)
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exec_sudo(cmd)
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# save state
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if 'pvs' not in self.state:
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self.state['pvs'] = {}
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self.state['pvs'][self.name] = {
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'opts': self.options,
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'device': phys_dev
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}
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def _cleanup(self):
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exec_sudo(['pvremove', '--force',
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self.state['pvs'][self.name]['device']])
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def get_edges(self):
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# See LVMNode.get_edges() for how this gets connected
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return ([], [])
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def create(self):
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# see notes in LVMNode object
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pass
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class VgsNode(NodeBase):
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def __init__(self, name, state, base, options):
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"""Volume Group
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This is a placeholder node for a volume group
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Arguments:
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:param name: Name of this node
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:param state: global state pointer
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:param base: Parent :class:`PvsNodes` this volume group exists on
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:param options: extra options passed to the `vgcreate` command
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"""
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super(VgsNode, self).__init__(name, state)
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self.base = base
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self.options = options
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def _create(self):
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# The PV's have saved their actual device name into the state
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# during their _create(). Look at our base elements and thus
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# find the underlying device paths in the state.
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pvs_devs = []
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for pv in self.base:
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pvs_dev = self.state['pvs'][pv]['device']
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pvs_devs.append(pvs_dev)
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cmd = ["vgcreate", ]
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cmd.append(self.name)
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cmd.extend(pvs_devs)
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if self.options:
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cmd.extend(self.options)
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logger.debug("Creating vg command [%s]", cmd)
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exec_sudo(cmd)
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# save state
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if 'vgs' not in self.state:
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self.state['vgs'] = {}
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self.state['vgs'][self.name] = {
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'opts': self.options,
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'devices': self.base,
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}
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def _cleanup(self):
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exec_sudo(['vgchange', '-an', self.name])
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exec_sudo(['vgremove', '--force', self.name])
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def get_edges(self):
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# self.base is already a list, per the config. There might be
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# multiple pv parents here.
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edge_from = self.base
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edge_to = []
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return (edge_from, edge_to)
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def create(self):
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# see notes in LVMNode object
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pass
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class LvsNode(NodeBase):
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def __init__(self, name, state, base, options, size, extents):
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"""Logical Volume
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This is a placeholder node for a logical volume
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Arguments:
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:param name: Name of this node
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:param state: global state pointer
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:param base: the parent volume group
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:param options: options passed to lvcreate
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:param size: size of the LV, in MB (this or extents must be provided)
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:param extents: size of the LV in extents
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"""
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super(LvsNode, self).__init__(name, state)
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self.base = base
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self.options = options
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self.size = size
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self.extents = extents
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def _create(self):
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cmd = ["lvcreate", ]
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cmd.extend(['--name', self.name])
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if self.size:
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cmd.extend(['-L', self.size])
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elif self.extents:
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cmd.extend(['-l', self.extents])
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if self.options:
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cmd.extend(self.options)
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cmd.append(self.base)
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logger.debug("Creating lv command [%s]", cmd)
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exec_sudo(cmd)
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# save state
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self.state['blockdev'][self.name] = {
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'vgs': self.base,
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'size': self.size,
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'extents': self.extents,
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'opts': self.options,
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'device': '/dev/mapper/%s-%s' % (self.base, self.name)
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}
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def _cleanup(self):
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exec_sudo(['lvchange', '-an',
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'/dev/%s/%s' % (self.base, self.name)])
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exec_sudo(['lvremove', '--force',
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'/dev/%s/%s' % (self.base, self.name)])
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def get_edges(self):
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edge_from = [self.base]
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edge_to = []
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return (edge_from, edge_to)
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def create(self):
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# see notes in LVMNode object
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pass
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class LVMNode(NodeBase):
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def __init__(self, name, state, pvs, lvs, vgs):
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"""LVM Driver Node
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This is the "global" node where all LVM operations are driven
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from. In the node graph, the LVM physical-volumes depend on
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this node. This node then depends on the devices that the
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PV's require. This node incorporates *all* LVM setup;
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i.e. after the create() call here we have created all pv's,
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lv's and vg. The <Pvs|Lvs|Vgs>Node objects in the graph are
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therefore just dependency place holders whose create() call
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does nothing.
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This is quite important in the cleanup phase. In theory, you
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would remove the vg's, then the lv's and then free-up the
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pv's. But the process of removing these also removes them
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from the LVM meta-data in the image, undoing all the
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configuration. Thus the unwind process is also "atomic" in
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this node; we do a copy of the devices before removing the LVM
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components, and then copy them back (better ideas welcome!)
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As with creation, the cleanup() calls in the other nodes are
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just placeholders.
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Arguments:
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:param name: name of this node
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:param state: global state pointer
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:param pvs: A list of :class:`PvsNode` objects
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:param lvs: A list of :class:`LvsNode` objects
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:param vgs: A list of :class:`VgsNode` objects
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"""
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super(LVMNode, self).__init__(name, state)
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self.pvs = pvs
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self.lvs = lvs
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self.vgs = vgs
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def get_edges(self):
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# This node requires the physical device(s), which is
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# recorded in the "base" argument of the PV nodes.
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pvs = []
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for pv in self.pvs:
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pvs.append(pv.base)
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edge_from = set(pvs)
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# The PV nodes should then depend on us. i.e., we just made
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# this node a synchronisation point
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edge_to = [pv.name for pv in self.pvs]
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return (edge_from, edge_to)
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def create(self):
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# Run through pvs->vgs->lvs and create them
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# XXX: we could theoretically get this same info from walking
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# the graph of our children nodes? Would that be helpful in
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# any way?
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for pvs in self.pvs:
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pvs._create()
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for vgs in self.vgs:
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vgs._create()
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for lvs in self.lvs:
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lvs._create()
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def cleanup(self):
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# First do a copy of all physical devices to individual
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# temporary files. This is because the physical device is
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# full of LVM metadata describing the volumes and we don't
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# have a better way to handle removing the devices/volumes
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# from the host system while persisting this metadata in the
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# underlying devices.
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tempfiles = collections.OrderedDict() # to unwind in same order!
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for pvs in self.pvs:
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phys_dev = self.state['blockdev'][pvs.base]['device']
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target_file = tempfile.NamedTemporaryFile(delete=False)
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target_file.close()
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exec_sudo(['dd', 'if=%s' % phys_dev,
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'of=%s' % target_file.name])
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tempfiles[target_file.name] = phys_dev
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# once copied, start the removal in reverse order
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for lvs in self.lvs:
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lvs._cleanup()
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for vgs in self.vgs:
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vgs._cleanup()
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for pvs in self.pvs:
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pvs._cleanup()
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exec_sudo(['udevadm', 'settle'])
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# after the cleanup copy devices back
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for tmp_name, phys_dev in tempfiles.items():
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exec_sudo(['dd', 'if=%s' % tmp_name, 'of=%s' % phys_dev])
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os.unlink(tmp_name)
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class LVMPlugin(PluginBase):
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def _config_error(self, msg):
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raise BlockDeviceSetupException(msg)
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def __init__(self, config, defaults, state):
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"""Build LVM nodes
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This reads the "lvm:" config stanza, validates it and produces
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the PV, VG and LV nodes. These are all synchronised via a
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LVMNode as described above.
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Arguments:
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:param config: "lvm" configuration dictionary
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:param defaults: global defaults dictionary
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:param state: global state reference
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"""
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super(LVMPlugin, self).__init__()
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# note lvm: doesn't require a base ... the base is the
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# physical devices the "pvs" nodes are made on.
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if 'name' not in config:
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self._config_error("Lvm config requires 'name'")
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if 'pvs' not in config:
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self._config_error("Lvm config requires a 'pvs'")
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if 'vgs' not in config:
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self._config_error("Lvm config needs 'vgs'")
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if 'lvs' not in config:
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self._config_error("Lvm config needs 'lvs'")
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# create physical volume nodes
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self.pvs = []
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self.pvs_keys = []
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for pvs_cfg in config['pvs']:
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if 'name' not in pvs_cfg:
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self._config_error("Missing 'name' in pvs config")
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if 'base' not in pvs_cfg:
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self._config_error("Missing 'base' in pvs_config")
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pvs_item = PvsNode(pvs_cfg['name'], state,
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pvs_cfg['base'],
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pvs_cfg.get('options'))
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self.pvs.append(pvs_item)
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# create volume group nodes
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self.vgs = []
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self.vgs_keys = []
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for vgs_cfg in config['vgs']:
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if 'name' not in vgs_cfg:
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self._config_error("Missing 'name' in vgs config")
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if 'base' not in vgs_cfg:
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self._config_error("Missing 'base' in vgs config")
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# Ensure we have a valid PVs backing this VG
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for pvs in vgs_cfg['base']:
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if not any(pv.name == pvs for pv in self.pvs):
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self._config_error("base:%s in vgs does not "
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"match a valid pvs" % pvs)
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vgs_item = VgsNode(vgs_cfg['name'], state, vgs_cfg['base'],
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vgs_cfg.get('options', None))
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self.vgs.append(vgs_item)
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# create logical volume nodes
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self.lvs = []
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for lvs_cfg in config['lvs']:
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if 'name' not in lvs_cfg:
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self._config_error("Missing 'name' in lvs config")
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if 'base' not in lvs_cfg:
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self._config_error("Missing 'base' in lvs config")
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if 'size' not in lvs_cfg and 'extents' not in lvs_cfg:
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self._config_error("Missing 'size' or 'extents' in lvs config")
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# ensure this logical volume has a valid volume group base
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if not any(vg.name == lvs_cfg['base'] for vg in self.vgs):
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self._config_error("base:%s in lvs does not match a valid vg" %
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lvs_cfg['base'])
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lvs_item = LvsNode(lvs_cfg['name'], state, lvs_cfg['base'],
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lvs_cfg.get('options', None),
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lvs_cfg.get('size', None),
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lvs_cfg.get('extents', None))
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self.lvs.append(lvs_item)
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# create the "driver" node
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self.lvm_node = LVMNode(config['name'], state,
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self.pvs, self.lvs, self.vgs)
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def get_nodes(self):
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# the nodes for insertion into the graph are all of the pvs,
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# vgs and lvs nodes we have created above, and the root node.
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return self.pvs + self.vgs + self.lvs + [self.lvm_node]
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